title: Effect of different coping designs on all-ceramic crown stress distribution: a finite element analysis.
abstract: OBJECTIVE
  To investigate the effect of differential coping designs on the stress distributions of an all-ceramic crown on, the upper central incisor under varying loads.
  
  
  METHODS
  3D finite element models with three differential coping designs of an all-ceramic crown on, the upper central incisor were constructed using CAD (computer aided design) software. The coping, designs included: CC (conventional coping), MCL (modified coping without veneer coverage in lingual, surface) and MCM (modified coping without veneer coverage in lingual margin). Loading that, simulated the maximum bite force (200 N) was applied to the crown at differential locations (incisal, edge, lingual fossa and lingual margin). The first principal stress values for the full crown were, calculated and expressed as stress intensity in MPa.
  
  
  RESULTS
  The simulations showed the stress distribution tendencies of the all-ceramic crown with, differential coping materials were similar. The stress concentration was found in the cervical region, coping/veneer layer interface and the loading area for both the coping layer and the veneer layer. Maximal stress value was observed in the loading area. Stress values varied for the three types of, coping designs; however, compared with CC and MCM, MCL exhibited the lowest stress values.
  
  
  CONCLUSIONS
  Modified coping without veneer coverage in the lingual side (MCL) proved promising in, preventing all-ceramic crown failures that originate from veneering porcelain, especially under, abnormal occlusal force.
authors.affiliation: Institute of Stomatology, Nanjing Medical University, NanJing 210029, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Hu
authors.forename: Ning
authors.initials: N
authors.lastname: Dai
authors.forename: Yidong
authors.initials: Y
authors.lastname: Bao
authors.forename: Weiping
authors.initials: W
authors.lastname: Gu
authors.forename: Junchi
authors.initials: J
authors.lastname: Ma
authors.forename: Feimin
authors.initials: F
authors.lastname: Zhang
mesh_terms: D002516:Ceramics; D003442:Crowns; D003801:Dental Veneers; D020342:Finite Element Analysis; D013314:Stress, Mechanical
keywords: All-ceramic crown; Coping design; Stress distribution; Three-dimensional finite element